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Topic Review (Newest First)

09-19-2012 09:09 AM

my87Z

since you mocked it up with a comp 270H cam i would say just use that cam. IMHO they are a pretty decent cam for a mild build where you may want a tiny bit of that lope from a larger cam. it wont be too much. i would strongly suggest changing out those 3.08:1 gears though, since this is a 4x4 i would guess that you and your son are looking at tires in the 33x12.5" range and right of hand i'm not sure if they were still using the th350 in 84' for the 1500 trucks or if they had already switched over to the 700R4. honestly either way a set of 4.10's is almost nescessary

09-18-2012 01:13 PM

compje

I have about 2500 in it now and its ready to drop in. I read a lot of posts talking about clearence problems. I just simply had none except for a little work at the bottom of the cylinders. Really an easy build. It will be fun getting this running and tuning it.

09-14-2012 08:18 PM

55_327

My 69 pickup once had a 383 with Dart Iron Eagle heads (2.02/1.60), 9.3:1 compression, and an old skool Crane Energizer 266 cam at 266/266, 210/210, .440", .440". Manifold was a low rise Edelbrock 2101, although today I'd use a more modern Weiand Street Warrior. Carb was a 600 CFM Edelbrock. Even with a 3.08 axle, that thing would just shred the tires! Torque was just insane from right off idle, and the engine would rev to almost 5000, although HP probably peaked at 4500. Almost forgot -- I used a Hughes 2000 stall converter on the TH-350 trans. Not sure I'd do that today, because it slipped 100-150 RPM more than stock at 60 MPH. And since the long stroke of a 383 will raise the actual stall speed of a stock converter, that's probably all you need with a small cam like I used.

By the way, SCAT makes an I-beam rod with 7/16" cap screws (not bolt/nut) that will clear a lot of cams. Best way to check is with a flashlight and .060" feeler gauge. And you can't just check one cylinder, although I think there are only 2 (or 4?) that have the potential for trouble. Wish I could remember the numbers!

Also, be sure to search this site and others for how-to articles on relieving the block.

09-11-2012 07:31 PM

chappybob

Quote:

Originally Posted by compje

I am new to this site and lookinf for other peoples experiences with building 383 strokers. I am in the process of building a 383 for my son's truck.

He has a 1984 silverado 4wd that is in excellent condition except it has a weezy 305 in it.

I purchased a 350 complete from a junk yard.
I ordered a complete 383 rotating assembly from scat. Should be close to 9.6/1 compression ratio when completed.
The block is going to be .040 over. (not exactly a 383 now)

The heads are .194/160 but I am having the machine shop hog them out for .202 intake valves. Looking for high port velocity for low end torque.

I have an Edlebrock performer intake, performer 650 carb, 1 5/8 tube headers with new magnaflow exhaust, 2 1/4 out the back, MSD streetfire ignition,,, basicly the same stuff we see all over the place.

I have not ordered a cam yet. I hear that I need a small base circle cam and I hear I dont because of the ARP ROD bolts are designed for this app and no need.

I will clearence the block in my shop when I get the block back as needed. (this is one of the reasons I went to the external balance, the other is windage and I needed a new balancer and flex plate, the kit comes complete.

This build will get roller rockers.

Any suggestions on cam. Looking for a truck motor with power low in the RPM range.

Hello,
I'm new to this forum, but not to the 383 strioker.
I build a.040 over 385 a few years ago. I built something that sounds nearly what you are doing. I had the shop put 202's in my heads also. I'm not sure if it made a difference or not. If I were doing it again I may save the money,and put it in the cam. I used a Competition Cams Extreme Energy 262 cam. Great torque. I don't think they offer that exact number today. I believe they make a can for 4x4's these days. Have fun... Bob

09-11-2012 07:07 PM

twinpilot001

Ive got the same setup=scar & all forged - I am using a cam from Howards - small base yet a higher life & solid too .

I am new to this site and lookinf for other peoples experiences with building 383 strokers. I am in the process of building a 383 for my son's truck.

He has a 1984 silverado 4wd that is in excellent condition except it has a weezy 305 in it.

I purchased a 350 complete from a junk yard.
I ordered a complete 383 rotating assembly from scat. Should be close to 9.6/1 compression ratio when completed.
The block is going to be .040 over. (not exactly a 383 now)

The heads are .194/160 but I am having the machine shop hog them out for .202 intake valves. Looking for high port velocity for low end torque.

I have an Edlebrock performer intake, performer 650 carb, 1 5/8 tube headers with new magnaflow exhaust, 2 1/4 out the back, MSD streetfire ignition,,, basicly the same stuff we see all over the place.

I have not ordered a cam yet. I hear that I need a small base circle cam and I hear I dont because of the ARP ROD bolts are designed for this app and no need.

I will clearence the block in my shop when I get the block back as needed. (this is one of the reasons I went to the external balance, the other is windage and I needed a new balancer and flex plate, the kit comes complete.

This build will get roller rockers.

Any suggestions on cam. Looking for a truck motor with power low in the RPM range.

Which SCAT 383 kit did you order? Versions using cap screw rods usually don't have clearance problems. You really want to avoid using a small base circle cam they put a lot of odd loads on the valve train causing them not to wear well on the street where cam replacement from wear is not desirable, for racing it's just something you put up with. For the most part the interference with the cam only occurs with the number 2 and 7 cylinders so if it's necessary to relieve the rods it's only those two. For an engine of moderate power even relieving on the upper bolt head of these two rods has not been shown to be a problem. With a cap screw rod such as the SCAT that usually comes with these stroker kits there usually is no clearance problem with the camshaft. I’m less than a fan of external balance, but for a street engine of moderate power and RPM, this is a reasonable approach that keeps the cost down.

Heads are big subject and cannot be addressed without including consideration for cam timing and piston crown shapes, (toss deck clearance and gasket thickness in there as well) So the upfront question is what are the casting numbers of the heads you have. Many older heads leave a lot of performance on the table. For performance I mean the whole subject, not just horsepower on the crank. Include in that fuel burn rate, effectiveness and efficiency, resistance to detonation and preignition, etc. Modern thought on this subject is to use a tight chambered head with a D dish piston, the dish volume to control overall compression for the grade fuel you want to use. The problem in using open chamber heads with a flat top piston is that while the flat top is desirable from a combustion stand point these type heads often place the spark plug well away from the center of the head which adds time for the burn to get across the chamber making the head more sensitive to detonation and preignition which causes you to run richer mixtures and or decrease the ignition advance all of which increase fuel consumption and reduce available power from what could be had. The small chamber head with a D dish in the piston gets the spark plug closer to the bore center reducing burn time which improves detonation and preignition resistance eliminating having to play games with the mixture ratio and ignition time that have less than optimal results on overall performance. This is the essence of modern fast burn heads.

My 85 c10 has a 305 and you might want to consider the costs. If it is a good 305 supercharge it. You will have plenty of power. Much more low and mid than a 268 xe cam 350. Never did the 383 stroker or 400 but the cost to complete would be more than 2k. In a heavy truck do you want to wind it out, or have the grunt from a supercharger. Either way stroking results never impressed me much. You should be fine with .480 lift , but gear up to 4.10 unless it has small tires.

09-09-2012 11:00 PM

compje

thanks to all for the feedback. I mocked up the rotating assembly with no piston rings. I had no clearence problems with a comp cam 270,, 480 lift,, the pan rails were absolutly no issue. I had to clearence the bottom of a few bores though,,, only one rod, #3 was touching. I clearenced all of them the same to be a bit anal about it. The engine is complete with rolloer tip 1.5 rockers. I will use the performer manifold from the engine in the truck as well as the carb and ingition. The old engine has a "new top end" , headers etc, so the swap should be easy and will happen in about 2 weeks when i get home from a job out of town.
Everything i have read about the 383 made me a little vervous, but apparently, with my rods, not an issue. i have the rods with cap screws instead of studs with nuts. It seems the aftermarket has honed the kits for this build above what was available a few years ago.
I did perform some mild port work in my shop, just smoothed out the castings in the heads and matched the intake ports to the gaskets and smoothed the transition. I will do the same to the intake when it is swapped. When comlpleted and running, I will give feedback.

08-24-2012 01:44 PM

Cridder

Rod to cam interference

Quote:

Originally Posted by compje

I don't see many offerings in Small base circle cam. When I get the block back next week, I plan on doing a mock up assembly without piston rings and see if I have a clearance problem with the old cam. No one has been able to say yea or nea of the clearance issue.

400s with there long stroke used a shorter rod with a lower shoulder to clear the cam, when you use the longer 350 rods with there higher shoulder the edge of the bolt interferes with the cam on 4 of the rods 2 more so and one will hit depending on camshaft profile, i clearanced mine to 0.066'' on 4 rods by sanding to varying degrees, i used a little bench top belt sander, i made up feeler gauges attached on a peice of aluminum flat bar as go no go, and a light i could drop down in there to see better, the amount of material removed from the rod bolt edge is not considered to be significant to weakening it. also i put paint on the feelers to leave a witness mark so i new presicly were to grind off material. my rods are the LT-1 PM jobs

08-24-2012 12:33 PM

68NovaSS

Take some time and do a site search here, if the software would allow it, you would get thousands of hits and builds for 383's.

08-24-2012 10:44 AM

cdminter59

383 build just getting started

You probably will be fine with the scat rotating assembly. The problem you were talking about with the small base circle is when turning the crank the rod bolts would come in contact with the camshaft. Here is a list of camshafts for low end torque. XE256H 12-234-2 1000-5200 447/454 212/218; X4254 12-235-2 1000-5200 .447/.462 210/218; 260H 12-206-2 (49) 1200-5200 .440/.440 212/212.

08-23-2012 09:54 PM

vinniekq2

moderate duration,lower icl and medium to low lda.the kid will like it and and it will sound cool.making more low end

08-23-2012 09:40 PM

compje

Looking for low end torque. Hydraulic lifters. I see 500hp monsters all of the time, will build one later, this is for my son. If I dont need a small base circle, this is easier.

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